Giants’ first baseman for the day: Hector Sanchez

Bruce Bochy is using his fifth first baseman in five games, going from Brandon Belt to Buster Posey to Joaquin Arias to Michael Morse to today’s starter, Hector Sanchez.

Belt underwent surgery today to fix his broken left thumb. He’ll miss at least six weeks.

Is Sanchez prepared for first base?

“He better be. I put him out there,” said Bochy, adding Sanchez earned the nod because of his hot bat: 353 with two homers and 13 RBIs in 34 at-bats.

“I think he can handle it. With Belt out, we’ve got to get a little creative here.”

Sanchez certainly seems prepared. He loved playing first in a spring-training game and promised to have fun at first tonight.

“It’s not much different between catching and first base. Just block the ball, and that’s it,” he said, not totally in jest.

After the spring game in which Sanchez made consecutive impressive plays, Tim Lincecum quipped, “I think Belt’s got to look out for his job right now.”

Bochy reiterated Michael Morse will get most the time at first base.

Sanchez will use a first baseman’s mitt (Wilson A2000) that was a gift from catching prospect Andrew Susac. “My little brother,” said Sanchez, who personalized the mitt by writing No. 29 on it with a sharpie – “to make sure nobody steals it. I broke it in, so it’s in good shape.”

Belt’s surgery was performed by Dr. Tim McAdams at the Stanford Medical Center. Belt is due to return to the park on Wednesday and accompany the team (except for next week’s trip to Denver) to get treatment.